Goal:
  
  A : Type
  B : Type
  C : Type
  P : nat → A → B → Type
  Q : B → C → Type
  R : nat → A → C → Type
  S : nat → A → C → Type
  y0 : C
  l' : list C
  n : nat
  x : A
  y : B
  l : list A
  r : list B
  r0 : P n x y
  a : All2i P (Datatypes.S n) l r
  q : Q y y0
  b : All2 Q r l'
  c : All2i R n (x :: l) (y0 :: l')
  ============================
   ((∀ (n : nat) (x : A) (y : B) (z : C), P n x y → Q y z → R n x z → S n x z)
    → (∀ l'' : list C,
         All2 Q r l''
         → All2i R (Datatypes.S n) l l'' → All2i S (Datatypes.S n) l l'')
      → let H := CoreTactics.block in All2i S n (x :: l) (y0 :: l'))


DEBUG:Going to execute:
CoreTactics.block_goal
Level 14: evaluation returns
idtac of type tacvalue

Level 12: evaluation returns
idtac of type tacvalue

Level 11: evaluation returns
idtac of type tacvalue

Level 9: evaluation returns
idtac of type tacvalue

Level 7: evaluation returns
idtac of type tacvalue

Level 6: evaluation returns
idtac of type tacvalue

Level 4: evaluation returns
idtac of type tacvalue

Level 2: evaluation returns
idtac of type tacvalue

Level 1: evaluation returns
idtac of type tacvalue